Key Technology Research Of Tri-system Satellite Navigation Receiver

This paper do some research of three key technology of tri-system satellitenavigation receiver. They are bit synchronization algorithm, carrier doppler filter and receiver autonomous integrity monitoring algorithm.Bit synchronization algorithm belongs to baseband processing. It’s important for receiver to correctly acquire navigation data and pseudorange. Three different bit synchronization algorithms are compared, which are histogram method, optimized histogram method and K-P algorithm. Result is that histogram method is suitable for high SNR circumstance and it has small amount of computations, but under low SNR situation, it has high probability of wrong bit synchronization; K-P algorithm has large amount of computations, but it has the highest probability of correct synchronization, even under low SNR circumstance; Optimized histogram method acquire balance between amount of computations and correct probability of synchronization.The accuracy of carrier doppler frequency directly influence the accuracy of receiver’s speed measurement. The accuracy of carrier doppler can be improved through filtering algorithm. Two algorithms are used. One is FIR filter, which is to remove out-of-band noise. The other one is Kalman filter, which can remove in-band noise. The accuracy of receiver’s velocity measurement is hugely promoted after using these two algorithms.Receiver autonomous integrity monitoring algorithm is used to detect and exclude wrong observation caused by satellite malfunction, signal interference, receiver fault and other factors, so receiver can correctly do position and navigation calculations continuously. The algorithm is discussed from positioning and speed measuring. The test result indicates that this algorithm can avoid trip point of positioning result efficiently.